Differential radioactivity monitor for noninvasive detection of ocular melanoma.

A novel instrument for the noninvasive diagnosis of ocular melanoma was evaluated with 67Ga in patients with pathologically confirmed tumours. The decision to enucleate was based on the results of standard ophthalmic diagnostic modalities including the 32P uptake test. The differences in the ocular radioactivity at 48-72 h predicted the presence of ocular abnormality. A positive differential result was found for tumours having a volume of greater than 600 mm3. Smaller tumours indicated lower retention of 67Ga in the eye with the tumour, whereas control subjects showed less than 2% differences in the radioactivity present in either eye.